The recent evolution of various electronics technologies now allows instruments to measure input data signals that are extremely large, and comprise a great number of samples. These larger data signals, and the great number of samples associated therewith require more and more memory to record the great amount of data associated therewith. In addition to merely storing this extensive amount of data in memory, this data must be somehow displayed to let the user analyze the input and sampled data signal.
A conventional procedure for drawing a signal on a screen is to draw a line joining each pair of sample points representing the captured signal. After connection of all of the data points a continuous line is presented to the user as an approximation of the received and sampled signal. While this method works fine with a small number of data sample points, as soon as the number of data points increases, this method becomes very slow. This is because drawing of each line by the display device requires hardware access from the main processor to the display device that is a very slow operation as compared to the processor capability. The most advanced instruments can now acquire multiple millions of samples. However, displaying millions of samples by drawing millions of lines between these samples is a very slow process, and can take up to several seconds.
In accordance with the invention, in order to avoid the problem of such a slow display, it is desirable to reduce to a minimum the number of times the display device is accessed. Therefore, in accordance with the invention, stored data is compacted before being forwarded to the display. Such a compaction may be performed when the number of data sample values is greater than the horizontal number of pixels of the display device. In such a situation, because the number of data sample values is greater than the number of pixels that can be displayed, multiple data values would xe2x80x9chitxe2x80x9d and be displayed at the same vertical pixel column, resulting in a difficult to view display. This is because multiple lines will be drawn overlapping each other vertically along the same pixel column.
Therefore, in accordance with the invention a compaction algorithm comprises examining every data value that would normally xe2x80x9chitxe2x80x9d or be displayed at a common vertical pixel column to determine the minimum and the maximum values of such data. Then using this min/max pair a single vertical line is drawn at the appropriate vertical pixel column to represent all of the data values corresponding to the pixel column, instead of drawing a multitude of overlapped vertical lines. This method is then applied to every vertical pixel column to be displayed on the display device. The invention also comprises the steps necessary to insure that data values are associated with the appropriate vertical pixel column.
In accordance with the invention, a clearer and easier display of an acquired signal is provided. Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification and the drawings.
The invention accordingly comprises several steps and the relation of one or more of such steps with respect to each other, and the apparatus embodying features of construction, combinations of elements and arrangement of parts that are adapted to effect such steps, all as exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.